Ligation clip with flexible clamping feature

ABSTRACT

A polymeric surgical ligating clip is provided having curved leg members joined by a resilient hinge. A leg member includes a flexible rib protruding from a vessel clamping inner surface and extends longitudinally between the proximal and distal end portions of the leg member. The flexible rib defines a channel extending transversely through the rib along a majority of said length. The flexible rib can collapse and provides better retention of the clip on a vessel. The clip can contain a flexible rib on both legs in an interlocking fashion. Or a plurality of teeth can protrude from a second vessel clamping inner surface of a second leg member. The plurality of teeth can include first and second rows of teeth extending longitudinally on the second leg member, transversely separated from each other on opposite sides of a centerline of the clip.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation application and claims thepriority benefit of co-pending U.S. patent application Ser. No.11/967,733, filed on Dec. 31, 2007, the disclosure of which is herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to medical devices and in particularsurgical clips for ligation of vessels or tissue.

BACKGROUND OF THE INVENTION

Many surgical procedures require vessels or other tissues of the humanbody to be ligated during the surgical process. For example, manysurgical procedures require cutting blood vessels (e.g., veins orarteries), and these blood vessels may require ligation to reducebleeding. In some instances, a surgeon may wish to ligate the vesseltemporarily to reduce blood flow to the surgical site during thesurgical procedure. In other instances a surgeon may wish to permanentlyligate a vessel. Ligation of vessels or other tissues can be performedby closing the vessel with a ligating clip, or by suturing the vesselwith surgical thread. The use of surgical thread for ligation requirescomplex manipulations of the needle and suture material to form theknots required to secure the vessel. Such complex manipulations aretime-consuming and difficult to perform, particularly in endoscopicsurgical procedures, which are characterized by limited space andvisibility. By contrast, ligating clips are relatively easy and quick toapply. Accordingly, the use of ligating clips in endoscopic as well asopen surgical procedures has grown dramatically.

Various types of hemostatic and aneurysm clips are used in surgery forligating blood vessels or other tissues to stop the flow of blood. Suchclips have also been used for interrupting or occluding ducts andvessels in particular surgeries such as sterilization procedures.Typically, a clip is applied to the vessel or other tissue by using adedicated mechanical instrument commonly referred to as a surgical clipapplier, ligating clip applier, or hemostatic clip applier. Generally,the clip is left in place after application to the tissue untilhemostasis or occlusion occurs.

Ligating clips can be classified according to their geometricconfiguration (e.g., symmetric clips or asymmetric clips), and accordingto the material from which they are manufactured (e.g., metal clips orpolymeric clips). Symmetric clips are generally “U” or “V” shaped andthus are substantially symmetrical about a central, longitudinal axisextending between the legs of the clip. Symmetric clips are usuallyconstructed from metals such as stainless steel, titanium, tantalum, oralloys thereof. But, with the advent of high technology diagnostictechniques using computer tomography (CATSCAN) and magnetic resonanceimaging (MM), metallic clips have been found to interfere with theimaging techniques. To overcome such interference limitations,biocompatible polymers have been increasingly used for surgical clips.

Some well known polymeric clips are disclosed in U.S. Pat. No. 4,834,096to Oh et al. and U.S. Pat. No. 5,062,846 to Oh et al., both of which arecommonly owned with the assignee of the present invention, thedisclosures of which are herein incorporated by reference in theirentirety. These plastic clips generally comprise a pair of curved legsjoined at their proximal ends with an integral hinge or heel.

Although plastic ligating clips are well known in the surgical area andimprovements have been made to the ligating clips, including providingprotrusions on the inner surfaces of the leg members to impede thelateral movement of a vessel during clip closure (see, for example, theaforementioned U.S. Pat. Nos. 4,834,096 and 5,062,846), theseimprovements have been less effective in preventing movement of the clipalong the length of a vessel or tissue during and after clip closure.One potential improvement in this area is disclosed in commonly-ownedU.S. Patent Application Pub. No. 2005/0165423 A1 by Gallagher et al.,the disclosure of which is incorporated by reference in its entirety,which discloses a polymeric surgical clip having an interlockingtongue-in-groove mechanism formed by a lip or tongue protruding from aportion of the inner surface of one leg and a groove formed in acorresponding portion of the inner surface of the other leg; or alock-step mechanism, formed by complementary L-shaped notches wherein anotch is provided in a portion of the inner surface of each leg. Theinterlocking mechanisms act to impede movement of the clip relative tothe vessel being clamped.

In all of the known ligating clips however, there remains a need toimprove the effectiveness of clamping about a vessel, while minimizingthe damage to the vessel and surrounding tissue. The occlusion of thevessel by a ligating clip can accidentally damage the vessel or severeit. Therefore, a ligating clip must have a sufficient degree of clampingforce and retention on a vessel, so as not to move relative to thevessel when applied, while also preserving tissue integrity andminimizing damage. Accordingly, there is a need to provide an improvedsurgical ligating clip with that serves to secure the tissue or vesselengaged by the clip, while robustly remaining attached to the vesselwith a minimum level of damage to tissue.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one aspect a ligation clip is provided thatincludes a flexible collapsible rib extending along an inner vesselclamping surface of one or both of the legs of the clip, providing forbetter, safer, and more robust retention of the clip on the vessel. Asingle flexible rib on one leg can be used with a plurality ofprotrusions or teeth disposed on the opposite leg, defining aninterlocking mechanism for improved vessel clamping and retention. Thepresent invention can apply additional pressure on the vessel tissuethrough a cross-clamping action as well as applying pressure normal tothe tissue. These provide a tortuous path or surface for the vesseltissue and increase the area of the tissue being retained.

In accordance with one embodiment of the present invention, a ligatingclip is provided, including first and second curved leg members havingrespective proximal and distal end portions. The proximal end portionsare joined by a resilient hinge. The first and second curved leg membershave respective first and second vessel clamping inner surfaces facingeach other when the first and second leg members are moved from an openposition to a closed position about the hinge. the first leg member hasa flexible rib protruding from the first vessel clamping inner surfaceand extending longitudinally a length between the proximal and distalend portions of the first leg member. The flexible rib defines a channelextending transversely through the rib along a majority of said length.

In accordance with another aspect of the present invention, a ligatingclip defining a longitudinal length of said clip is provided, includingtwo leg members having respective proximal and distal end portions. Theproximal end portions are joined by a resilient hinge. The two legmembers have respective vessel clamping inner surfaces facing each otherwhen the two leg members are moved from an open position to a closedposition about the hinge. At least one flexible rib is included on atleast one of said leg members and extends along a vessel clamping innersurface of said at least one leg member along a majority of alongitudinal span of said vessel clamping inner surface. The at leastone flexible rib includes a longitudinal span member spaced from therest of said at least one leg member. The longitudinal span member isconnected to said at least one leg member at the respective proximal anddistal end portion of said leg member.

In accordance with yet another aspect of the present invention, aligating clip is provided, having first and second curved leg membershaving respective proximal and distal end portions. The proximal endportions are joined by a resilient hinge. The first and second curvedleg members have respective first and second vessel clamping innersurfaces facing each other when said first and second leg members aremoved from an open position to a closed position about said hinge. Thefirst leg member has a first flexible rib protruding from said firstvessel clamping inner surface and extending longitudinally a firstlength between the proximal and distal end portions of the first legmember. The first flexible rib defines a first channel extendingtransversely through the first rib along a majority of said firstlength. The second leg member includes a second collapsible, flexiblerib protruding from said second vessel clamping inner surface andextending longitudinally a second length between the proximal and distalend portions of the second leg member. The second flexible rib defines asecond channel extending transversely through said second rib along amajority of said second length.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof herein may bebetter understood, and in order that the present contribution to the artmay be better appreciated. There are, of course, additional embodimentsof the invention that will be described below and which will form thesubject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged side elevation view of one embodiment of asurgical ligating clip of the present invention.

FIG. 2 is an enlarged perspective view of the embodiment of FIG. 1.

FIG. 3 is another enlarged perspective view of the embodiment of FIG. 1.

FIG. 4 is an enlarged side elevation view of another embodiment of asurgical ligating clip of the present invention.

FIG. 5 is an enlarged perspective view of the embodiment of FIG. 4.

FIG. 6 is an enlarged side elevation view of the surgical ligating clipin FIGS. 1-3 in a closed position.

FIG. 7 is an enlarged side elevation view of the surgical ligating clipin FIGS. 4-5 in a closed position.

DETAILED DESCRIPTION

The invention will now be described with reference to the drawingfigures, in which like reference numerals refer to like partsthroughout. In accordance with conventional practice, as used herein,and unless otherwise indicated herein, the term “proximal” or “proximalend” shall refer to the specified end of a device or its component whichis generally closer to the medical personnel handling or manipulatingthe device as it is intended to be used, and the term “distal” or“distal end” shall refer to the specified end of a device or itscomponent which is opposite the proximal end.

The present invention involves a surgical ligating clip, preferably madeof a polymeric material, which can be used to clamp vessels such asarteries in the body, having a pair of asymmetric, curved concave-convexlegs, and including one or more flexible rib portions as well as rows ofprotruding teeth to provide an improved and superior interlocking meansto retain the clip on a vessel. The surgical clip of the presentinvention includes one or more flexible ribs to apply additionalpressure on the tissue of the vessel being ligated, and can additionallyprovide a cross-clamping action as well as applying pressure normal tothe tissue. Additional features of the present invention includeexaggerated teeth on either side of the centrally located flexible ribs,which provides a tortuous path and surface for the tissue and increasesthe area of the tissue being retained by the clip.

FIG. 1 is an enlarged side elevation view of one embodiment of asurgical ligating clip of the present invention, designated generally as100. FIG. 2 and FIG. 3 show alternative perspective view of the surgicalclip 100. Clip 100 and others of similar design are particularly usefulas hemostatic clips that can be latched around a vessel or other type oftissue to ligate the vessel and thereby stop or reduce the flow of fluidthrough the vessel.

The body of clip 100 includes a first leg member 102 having a proximalend portion 102A and distal end portion 102B, and a second leg member104 having a proximal end portion 104A and distal end portion 104B. Asused herein, the term “longitudinal” and a “longitudinal” direction orspan shall mean the dimension along clip 100 or legs 102 or 104 whichextends along the length of said legs from their respective proximal endportions 102A, 104A to their respective distal end portions 102B, 104B,as would be commonly understood by one of skill in the art, and as shownin FIG. 1 as longitudinal axes L1 and L2. Furthermore, as used herein,the “transverse” direction shall be any axis or direction which isorthogonal of longitudinal axes L1 and L2, which would be normal to theplane of view in FIG. 1.

First and second legs 102 and 104 are joined at their proximal ends byan integral resilient hinge section, generally designated 106. First andsecond legs 102 and 104 are curved and have complementary arcuateprofiles, and include respective inner vessel clamping surfaces. Thus,as best shown in FIG. 1, first leg 102 has a concave inner vesselclamping surface 108 and a convex outer surface 110, and second leg 104has a convex inner vessel clamping surface 112 and a concave outersurface 114. Convex inner surface 112 of second leg 104 and concaveinner surface 108 of first leg 102 have substantially matching radii ofcurvature.

Hinge section 106 has a continuous concave inner surface 116 and acontinuous convex outer surface 118. Concave inner surface 116 of hinge106 joins concave inner surface 108 of first leg 102 and convex innersurface 112 of second leg 104. Convex outer surface 118 of hinge section106 joins convex outer surface 110 of first leg 102 and concave outersurface 114 of second leg 104. Curved slot 120 is located between curvedhinge surfaces 116 and 118, and is positioned closer to inner surface116 than to outer surface 118. Slot 120 extends completely through hingesection 106 from side to side and its opposite ends 122, 124 extend intothe proximal ends of first and second legs 102 and 104, respectively.Slot 120 provides added flexibility and resiliency to hinge section 106,but the inner concave surface 116 prevents any portion of a clampedvessel from being trapped within slot 120.

First leg 102 transitions to a curved, C-shaped hook section 126 at itsdistal end. Second leg 104 transitions to a pointed tip section 128 atits distal end. The distal portion of hook section 126 curves inwardlyand points generally toward inner surface 116 of hinge 106. The hooksection 126 has a transverse beveled surface 130 and a concave innersurface which mates with concave inner surface 108 to define a latchingrecess 132. The latching recess 132 is adapted for conformally engagingtip section 128 in the course of compressing clip 100 into a latched orlocked position around a vessel or other tissue.

Clip 100 further includes a flexible rib 134 disposed on the firstvessel clamping inner surface 108 on the first leg member 102. Flexiblerib 134 protrudes from said first leg member 102 and extendslongitudinally a length between the proximal 102A and distal 102B endportions of the first leg member 102. The flexible rib 134 defines achannel 135 which extends transversely through said rib 134 along amajority of the length of the rib 134. In the embodiment of FIGS. 1through 3, the channel 135 stretches along a majority of the overalllongitudinal length of the rib 134, but it is understood that saidchannel 135 can also accommodate varying arrangements including one ormore discrete transverse channels through the rib 134, located atvarying positions and longitudinal spans along the rib 134.

Clip 100 can be constructed from any suitable biocompatible material,such as certain metals and polymers. However, the present invention isparticularly suitable for practice with polymeric clips. Thus, clip 100preferably comprises a one-piece integral polymeric body formed from asuitable strong biocompatible engineering plastic such as the typecommonly used for surgical implants. Examples include polyethyleneterephthalate (PET), polybutylene terephthalate (PBT), polyoxymethylene,or other thermoplastic materials having similar properties that can beinjection-molded, extruded or otherwise processed into like articles.

In the embodiment shown in FIGS. 1-3, flexible rib 134 includes alongitudinal span member 136 spaced from the rest of the leg member 102by virtue of the channel 135 therebetween. The longitudinal span member136 is connected to leg member 102 at the respective proximal 102A anddistal 102B end portions of said leg member, as best shown in FIG. 1.This particular structural configuration of flexible rib 134 renders itsomewhat collapsible, such that, upon closure of the clip 100 around avessel, the rib 134 will flex and collapse towards the leg 102 and moreeffectively grip and retain tissue, while minimizing potential damage tosaid tissue. FIG. 6 is an enlarged side elevation view of the surgicalligating clip in FIGS. 1-3 in a closed position.

In the embodiment shown in FIGS. 1-3, the clip 100 can include aplurality of teeth 137 protruding on the second vessel clamping innersurface 112 on the second leg member 104. As best shown in FIG. 3, theplurality of teeth 137 include first 137A and second 137B rows of teethextending longitudinally between the proximal 104A and distal 104B endportions of the second leg member 104, the first row 137A beingtransversely separated from the second row 137B on opposite sides of acenterline CL of the second vessel clamping inner surface 112. Thecenterline CL is also coincident with a centerplane of symmetry of theclip 100, said centerplane spanning the direction of longitudinal axesL1 and L2 (and parallel to the view of FIG. 1) and dividing clip 100into symmetric halves with the exception of the longitudinal staggeringof tooth rows 137A and 137B as best shown in FIG. 3. The transverseseparation of tooth rows 137A and 137B about centerline CL is justenough, or slightly greater, than the transverse width of flexible rib134 and its longitudinal span member 136, as best shown in FIG. 2.Flexible rib 134 is approximately centered between side surfaces 138 and140 of first leg member 102 such that flexible rib 134 is alsopositioned on a centerline of vessel clamping surface 108 of first leg102, which centerline is also coincident with the centerplane of theclip 100 and mates with the centerline CL of surface 112 on second leg104, such that when the clip 100 is closed about a vessel, the flexiblerib 134 fits into the transverse separation between rows of teeth 137Aand 137B, providing a tortuous path or surface for tissue being clamped,and increasing the effective area of tissue being retained by clip 100over the prior art, as well as increasing the effective pressure beingapplied to the tissue by clip 100.

As shown in the embodiment of FIGS. 1-3, because first leg member 102has a concave radius of curvature, viewed relative to facing the firstvessel clamping inner surface 108, and the second leg member 104 has aconvex radius of curvature, viewed relative to facing the second vesselclamping inner surface 112, the length of flexible rib 134 also has aconcave radius of curvature when facing the first vessel clamping innersurface 108, such that the closure of clip 100 results in the variousradii of curvature mating to effectively close the clip 100 over avessel. The combination of flexible rib 134 and transversely separatedrows of teeth 137A and 137B on respective first and second vesselclamping inner surfaces 108 and 112 form an interlocking mechanism whichprovides improved, robust, flexible, and safer vessel retention by aligating clip over the prior art.

Adjacent to the distal end of the first leg 102 and immediately inwardof hook section 126, cylindrical bosses 146 and 148 protrudeperpendicular to each of the opposed side surfaces 138 and 140. In theillustrated example of clip 100, a bridge section 150 couples bosses 146and 148 together. As evident in FIGS. 1-3, bosses 146 and 148 projectoutwardly beyond convex outer surface 110 of first leg 102. At thedistal end of second leg 104, cylindrical bosses 152 and 154 protrudeperpendicular to each of the opposed side surfaces 142 and 144 of secondleg 104 and extend longitudinally forward beyond the point of tip 128.

In the practice of ligating a vessel as understood by persons skilled inthe art, clip 100 is designed to be compressed into a latched or lockedposition around the vessel through the use of an appropriate clipapplicator instrument, such as a type described in U.S. Pat. No.5,100,416. The clip applicator instrument engages bosses 146, 148, 152and 154 of clip 100 and pivots bosses 146, 148, 152 and 154 inwardlyabout hinge section 106. This causes first and second legs 102 and 104to close around the vessel, with convex inner surface 112 of second leg104 and complementary concave inner surface 108 of first leg 102contacting the outer wall of the vessel. Flexible rib 134 pushes aportion of the vessel into the transverse spacing between tooth rows137A and 137B, where the clamping pressure also pushes portions of thevessel into the longitudinal spacing between teeth on the two rows 137Aand 137B, all of which effectively secures the clip 100 to the vesseland prevents movement of the clip or vessel during or after clipclosure. Tip section 128 of second leg 104 also contacts hook section126. Pivotal movement by the applicator instrument longitudinallyelongates first leg 102 and deflects hook section 126, allowing tipsection 128 to align with latching recess 132. The hook member 126 canterminates in a sharp pointed tip at the convergence of beveled surface130, which extends toward the proximal end portion 102A of first legmember 102. The distal end of said second leg member 104 includes agroove 160 through which said sharp pointed tip 130 passes when the legmembers 102 and 104 are moved to the closed position about a vessel.Upon release of the applicator instrument, tip section 128 and groove160 snaps into and is conformably seated in latching recess 132 insidehook 126, at which point clip 100 is in its latched condition and thevessel securely engaged thereby.

FIGS. 4-5 depict an alternate embodiment of an asymmetric surgical clip200 in accordance with the invention. Clip 200 bears many similaritiesto clip 100 described above with reference to FIGS. 1-3. For example,the materials and procedures used to make and apply clip 100 may be usedto make and apply clip 200 as well. Similarly, the various features ofclip 100 described above are referenced where appropriate in FIGS. 4-5with respect to clip 200 using the same reference numerals used in FIGS.1-3.

FIG. 4 is an enlarged side elevation view of clip 200. The body of clip200 includes a first leg 202 having a proximal end portion 202A anddistal end portion 202B, and a second leg 204 having a proximal endportion 204A and a distal end portion 204B. First and second legs 202and 204 are joined at their proximal ends by integral hinge section 106.First and second legs 202 and 204 are curved and have complementaryarcuate profiles. Thus, first leg 202 has a concave vessel clampinginner surface 208 and a convex outer surface 110, and second leg 104 hasa convex vessel clamping inner surface 212 and a concave outer surface114. Convex inner surface 212 of second leg 104 and concave innersurface 208 of first leg 202 have substantially matching radii ofcurvature.

Hinge section 106 has a continuous concave inner surface 116 and acontinuous convex outer surface 118. Concave inner surface 116 of hinge106 joins concave inner surface 208 of first leg 202 and convex innersurface 212 of second leg 204. Convex outer surface 118 of hinge section106 joins convex outer surface 110 of first leg 102 and concave outersurface 114 of second leg 104. Curved slot 120 is located between curvedhinge surfaces 116 and 118, and is positioned closer to inner surface116 than to outer surface 118. Slot 120 extends transversely completelythrough hinge section 106 from side to side and its opposite ends 122,124 extend into the proximal ends of first and second legs 202 and 204,respectively. Slot 120 provides added flexibility and resiliency tohinge section 106, but the inner concave surface 116 prevents anyportion of a clamped vessel from being trapped within slot 120.

First leg 202 transitions to a curved, C-shaped hook section 126 at itsdistal end. Second leg 204 transitions to a pointed tip section 128 atits distal end. The distal portion of hook section 126 curves inwardlyand points generally toward inner surface 116 of hinge 106. The hooksection 126 has a transverse beveled surface 130 and a concave innersurface which mates with concave inner surface 208 to define a latchingrecess 132. The latching recess 132 is adapted for conformally engagingtip section 128 in the course of compressing clip 200 into a latched orlocked position around a vessel or other tissue.

As best shown in FIG. 5, clip 200 further includes two flexible ribs234A and 234B, one each disposed on the respective first vessel clampinginner surface 208 on first leg member 202 and second vessel clampinginner surface 212 on the second leg member 204. Flexible ribs 234A and234B protrude from respective first leg member 202 and second leg member204 and extend longitudinally a length between the respective proximal202A, 204A and distal 202B, 204B end portions of leg members 202, 204.The flexible ribs 234A and 234B each defines a respective channel 235Aand 235B which extend transversely through said ribs 234A and 234B alonga majority of the length of said ribs. In the embodiment of FIGS. 4-5,the channels 235A and 235B stretch along a majority of the overalllongitudinal length of the ribs 234A and 234B, but it is understood thatsaid channels 235A and 235B can also accommodate varying arrangementsincluding one or more discrete transverse channels through each rib 234Aand 234B, located at varying positions and longitudinal spans along saidribs. Alternatively, one of channels 235A or 235B can be missing suchthat one of ribs 234A or 234B is solid instead of hollow. Clip 200 canbe constructed from any suitable biocompatible material, such as certainmetals and polymers, such as previously discussed above with Clip 100.

The ribs 234A and 234B form complementary parts of an interlockingmechanism. In this embodiment, the complementary parts are arranged in alock-step, or scissor-like configuration. In the embodiment shown inFIGS. 4-5, flexible ribs 234A and 234B each include a respectivelongitudinal span member 236A and 236B spaced from the rest of theirrespective leg members 202 and 204 by virtue of the respective channels235A and 235B therebetween. The longitudinal span members 236A and 236Bare each connected to their respective leg members 202 and 204 at therespective proximal 202A, 204A and distal 202B, 204B end portions ofsaid leg members, as best shown in FIG. 4. This particular structuralconfiguration of flexible ribs 234A and 234B renders said ribs somewhatcollapsible, such that, upon closure of the clip 200 around a vessel,each rib 234A and 234B will flex and collapse towards their respectiveattached legs 202 and 204 and more effectively grip and retain tissue,while minimizing potential damage to said tissue.

As shown in FIG. 5, the first flexible rib 234A is disposed on a firstside of the clip 200, and the second flexible rib 234B is disposed on asecond side of the clip 200 opposite the first side. The ribs 234A and234B are thus offset of opposite of the longitudinal centerplane of theclip 200, creating the complementary parts of a scissor-likeinterlocking mechanism for ligating and retaining a vessel around whichclip 200 is clamped. As shown in FIGS. 4-5, the first flexible rib 234Ahas a concave radius of curvature when facing the vessel clamping innersurface 208, and the second flexible rib 234B has a convex radius ofcurvature when facing the vessel clamping inner surface 212.

Adjacent to the distal end of the first leg 202 and immediately inwardof hook section 126, cylindrical bosses 146 and 148 protrudeperpendicular to each of the opposed side surfaces 238 and 240. In theillustrated example of clip 200, a bridge section 150 couples bosses 146and 148 together. As evident in FIGS. 4-5, bosses 146 and 148 projectoutwardly beyond convex outer surface 110 of first leg 202. At thedistal end of second leg 204, cylindrical bosses 152 and 154 protrudeperpendicular to each of the opposed side surfaces 242 and 244 of secondleg 204 and extend longitudinally forward beyond the point of tip 128.

In the practice of ligating a vessel as understood by persons skilled inthe art, clip 200 is designed to be compressed into a latched or lockedposition around the vessel through the use of an appropriate clipapplicator instrument, in much the same manner as described above withrespect to clip 100. In clip 200 however, instead of a single flexiblerib on one leg fitting into rows of teeth disposed on the opposite legas in clip 100, the two flexible ribs 234A and 234B interlock togetherto provide a cross-clamping action as well as additional pressureapplied normal to tissue on a vessel. FIG. 7 shows the clip 200 in aclosed position.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

What is claimed is:
 1. A clip for ligating a vessel, the clipcomprising: first and second curved leg members having respectiveproximal and distal end portions, the proximal end portions being joinedby a hinge, a flexible rib on the first curved leg member extendinglongitudinally along a length from the proximal end portion to thedistal end portion of the first curved leg member, the flexible ribbeing attached spaced from the first curved leg member via at least twoattachment portions to define a channel extending transversely betweenthe flexible rib and the first curved leg member, a first pair of bossesextending transversely from opposite sides of the distal end portion ofthe first curved leg member, and a second pair of bosses extendingtransversely from opposite sides of the distal end portion of the secondcurved leg member, and first and second rows of teeth extendinglongitudinally on a vessel clamping inner surface of the second curvedleg member, the first and second rows of teeth being transverselyseparated from each other on opposite sides of a centerline of thevessel clamping inner surface, wherein the flexible rib is receivedbetween the first and second rows of teeth in a closed configuration. 2.The clip of claim 1, wherein the first curved leg member terminates at adistal end in a hook member curved toward the second curved leg member,the second curved leg member terminates at a distal end in acomplimentary locking portion to the hook member, and the hook member isconfigured to deflect about the distal end of the second curved legmember to lock the clip in the closed configuration when the first andsecond curved leg members are moved to the closed configuration.
 3. Theclip of claim 2, wherein the hook member terminates in a sharp pointedtip extending toward the proximal end portion of the first curved legmember, and the distal end of the second curved leg member includes agroove through which the sharp pointed tip passes when the first andsecond curved leg members are moved to the closed configuration.
 4. Theclip of claim 1, wherein the hinge is integral to the first and secondcurved leg members, the hinge is resilient, and the hinge includes acontinuous concave inner surface and a continuous convex outer surface.5. The clip of claim 1, wherein the teeth of the first row of teeth arelongitudinally separated from each other along the vessel clamping innersurface, and the teeth of the second row of teeth are longitudinallyseparated from each other along the vessel clamping inner surface. 6.The clip of claim 1, wherein the first and second rows of teeth arestaggered along the vessel clamping inner surface.
 7. The clip of claim1, wherein the first and second curved leg members have matching radiiof curvature.
 8. The clip of claim 1, wherein each of the first andsecond curved leg members has a curvature extending from the respectiveproximal end portion to the respective distal end portion.
 9. The clipof claim 1, wherein the vessel clamping inner surface of the secondcurved leg member has a convex radius of curvature facing the firstcurved leg member, and a vessel clamping inner surface of the firstcurved leg member has a concave radius of curvature facing the secondcurved leg member.
 10. A clip for ligating a vessel, the clipcomprising: first and second curved leg members having respectiveproximal and distal end portions, the proximal end portions being joinedby a hinge, and at least one flexible rib on the first curved legmember, the at least one flexible rib extending longitudinally along alength from the proximal end portion to the distal end portion of thefirst curved leg member, the flexible rib being attached spaced from thefirst curved leg member via at least two attachment portions to define achannel extending transversely between the flexible rib and the firstcurved leg member, and first and second rows of teeth extendinglongitudinally on a vessel clamping inner surface of the second curvedleg member, the first and second rows of teeth being transverselyseparated from each other on opposite sides of a centerline of thevessel clamping inner surface, wherein the at least one flexible rib isreceived between the first and second rows of teeth in a closedconfiguration, wherein the clip is configured to be independentlyretained without use of any external applier or tool on the vessel afterthe clip is applied to occlude the vessel, wherein the second curved legmember terminates at its distal end in a hook member curved toward thefirst curved leg member, the first curved leg member terminates at itsdistal end in a complimentary locking portion to the hook member, andthe hook member is configured to deflect about the distal end of thefirst curved leg member to lock the clip in the closed configurationwhen the first and second curved leg members are moved to the closedconfiguration, and wherein the hook member terminates in a sharp pointedtip extending toward the proximal end portion of the second curved legmember, and the distal end of the first curved leg member includes agroove through which the sharp pointed tip passes when the first andsecond curved leg members are moved to the closed configuration.
 11. Theclip of claim 10, wherein the first and second curved leg members haverespective first and second vessel clamping inner surfaces.
 12. The clipof claim 10, wherein the first curved leg member has a convex radius ofcurvature facing the second curved leg member, and the second curved legmember has a concave radius of curvature facing the first curved legmember.
 13. The clip of claim 10, further comprising: a first pair ofbosses extending transversely from opposite sides of the distal endportion of the first curved leg member, and a second pair of bossesextending transversely from opposite sides of the distal end portion ofthe second curved leg member.
 14. The clip of claim 10, wherein thehinge is integral to the first and second curved leg members, the hingeis resilient, and the hinge includes a continuous concave inner surfaceand a continuous convex outer surface.
 15. A clip for ligating a vessel,the clip comprising: first and second curved leg members havingrespective proximal and distal end portions and curved vessel clampinginner surfaces, the proximal end portions being joined by a hinge, a ribon the first curved leg member extending longitudinally on the curvedvessel clamping inner surface of the first curved leg member from therespective proximal end portion to the respective distal end portion,and first and second rows of teeth extending longitudinally on thecurved vessel clamping inner surface of the second curved leg member,the first and second rows of teeth being transversely separated fromeach other on opposite sides of a centerline of the curved vesselclamping inner surface of the second curved leg member, wherein the ribis received between the first and second rows of teeth in a closedconfiguration.
 16. The clip of claim 15, further comprising: a firstpair of bosses extending transversely from opposite sides of the distalend portion of the first curved leg member, and a second pair of bossesextending transversely from opposite sides of the distal end portion ofthe second curved leg member.
 17. The clip of claim 15, wherein thefirst curved leg member terminates at a distal end in a hook membercurved toward the second curved leg member, the second curved leg memberterminates at a distal end in a complimentary locking portion to thehook member, and the hook member is configured to deflect about thedistal end of the second curved leg member to lock the clip in theclosed configuration when the first and second curved leg members aremoved to the closed configuration.
 18. The clip of claim 15, wherein theteeth of the first row of teeth are longitudinally separated from eachother along the curved vessel clamping inner surface of the secondcurved leg member, and the teeth of the second row of teeth arelongitudinally separated from each other along the curved vesselclamping inner surface of the second curved leg member.
 19. The clip ofclaim 15, wherein the hinge is integral to the first and second curvedleg members, the hinge is resilient, and the hinge includes a continuousconcave inner surface and a continuous convex outer surface.
 20. Theclip of claim 15, wherein the first and second rows of teeth arestaggered along the curved vessel clamping inner surface of the secondcurved leg member.
 21. The clip of claim 15, wherein the curved vesselclamping inner surface of the first curved leg member and the curvedvessel clamping inner surface of second curved leg member have matchingradii of curvature.
 22. The clip of claim 15, wherein each of the firstand second curved leg members has a curvature extending from therespective proximal end portion to the respective distal end portion.23. The clip of claim 15, wherein the curved vessel clamping innersurface of the second curved leg member has a convex radius of curvaturefacing the first curved leg member, and the curved vessel clamping innersurface of the first curved leg member has a concave radius of curvaturefacing the second curved leg member.